OBJECTIVE: To characterize influenza viral messenger RNA. APPROACH: RNA complementary to virion RNA (or cRNA) is expected to be the viral messenger RNA (mRNA). Viral cRNA is being purified from the cytoplasm of infected cells, employing oligo dT-cellulose chromatography, which selects cRNA by virtue of its poly A segments, and Sepharose 4B chromatography, which separates single-stranded cRNA from double-stranded forms. Annealing experiments are being carried out to determine the purity of the cRNA preparation and whether it contains all the genetic information in the viral genome. The ability of the viral cRNA to direct the synthesis of virus-specific proteins in wheat germ cell-free extracts is being tested. The viral cRNA will be separated into its individual segments by gel electrophoresis, and it will be determined which segment codes for which virus-specific protein. Using methionine labeled in its methyl group as precursor, it will be determined whether, as with other mRNA's, the 5' terminus of cRNA consists of a 7-methyl guanosine "cap" structure.